Repositório Comunidade:http://hdl.handle.net/10362/3552
Tue, 31 Mar 2015 22:05:16 GMT2015-03-31T22:05:16ZAmyotrophic Lateral Sclerosis:Mammalian Cell Models,Copper-Zinc Superoxide Dismutaseand Biological Characteristicshttp://hdl.handle.net/10362/14114
Título: Amyotrophic Lateral Sclerosis:Mammalian Cell Models,Copper-Zinc Superoxide Dismutaseand Biological Characteristics
Autor: Gomes, Catarina Heitor
Resumo: "Amyotrophic Lateral Sclerosis (ALS) is the most severe and
common adult onset disorder that affects motor neurons in the spinal cord,
brainstem and cortex, resulting in progressive weakness and death from
respiratory failure within two to five years of symptoms onset(...)Fri, 01 Jan 2010 00:00:00 GMThttp://hdl.handle.net/10362/141142010-01-01T00:00:00ZThe role of Rac1-modulated gene transcription in tumorigenesishttp://hdl.handle.net/10362/8574
Título: The role of Rac1-modulated gene transcription in tumorigenesis
Autor: Barros, Patrícia
Resumo: Gene expression regulation is a dynamic and multi-step process,
in which transcription plays a major role. Transcription initiation depends
on binding of transcription regulators to DNA elements located in promoter
or enhancer regions, a process often controlled by signalling pathways.
One such pathway is regulated by Rac1, a member of the Rho family of
small GTPases involved in cell proliferation, adhesion and migration. In
this work, novel links between Rac1 signalling and transcriptional
regulation in colorectal tumour cells are described. First, it is shown that
Rac1 activation leads to PAK1-mediated phosphorylation of the
transcriptional repressor BCL-6 in colorectal cancer cells, inactivating its
repressor function. In the presence of active Rac1, BCL-6 redistribution
within the nucleus, a reduction in its affinity to chromatin and increased
expression of the endogenous target genes NFKB1 and CD44, and of a
BCL-6-controlled luciferase reporter construct were observed. Next, it was
found that Rac1 signalling promotes gene transcription by inducing a
transcriptional switch from the repressor BCL-6 to the activator STAT5A at
the promoter of certain target genes. Using chromatin
immunoprecipitation, it is demonstrated in different colorectal cell lines
that active Rac1 promotes release of BCL-6 with concomitant nuclear
translocation and binding of STAT5A at the same promoter site. Three
endogenous cell-cycle-related genes (CCND2, CDKN2B, SUMO1) were
identified to be inversely regulated by BCL-6 and STAT5A and shown to
respond to Rac1 signalling with promoter occupancy switches that
correlate directly with changes in their expression levels.(...)
Descrição: Dissertation presented to obtain the Ph.D degree in BiologyMon, 01 Oct 2012 00:00:00 GMThttp://hdl.handle.net/10362/85742012-10-01T00:00:00ZProtein glycosylation of exosomes from ovarian carcinoma cells: structures and biological roleshttp://hdl.handle.net/10362/6864
Título: Protein glycosylation of exosomes from ovarian carcinoma cells: structures and biological roles
Autor: Escrevente, Cristina
Resumo: Exosomes are small membrane vesicles that are secreted by
several cell types including tumour cells. They are formed intracellularly by
an inward budding of the membrane of endosomal compartments which are
converted to multivesicular bodies. Exosomes are then released into the
extracellular environment after fusion of the multivesicular bodies with the
plasma membrane. Upon internalization by other cells they may transfer
proteins and RNA among cells. Tumour-derived exosomes can promote
angiogenesis, cell proliferation, tumour cell invasion and immune evasion.
These vesicles have been found in biological fluids such as malignant
ascites and blood and can therefore be used not only to identify potential
biomarkers of disease but also in vaccination.(...)
Descrição: Dissertation presented to obtain the Ph.D. degree in BiologySat, 01 Oct 2011 00:00:00 GMThttp://hdl.handle.net/10362/68642011-10-01T00:00:00ZCharacterization of the glycosylation of human tumor cellshttp://hdl.handle.net/10362/4042
Título: Characterization of the glycosylation of human tumor cells
Autor: Machado, Eda
Resumo: Ovarian cancer is within the most lethal gynecological malignancies
in woman. Therefore, many investigators study its biological aspects with
the purpose of discovering more rapid diagnostic methods and efficient
treatment. Resembling many other tumors, in ovarian cancer, aberrant
glycosylation occurs with the appearance of novel or altered carbohydrate
structures. These can be terminal motifs, such as the Lewis determinants,
or entire carbohydrate sequences, which have been related to
tumorigenesis and its outcome.(...)Sat, 01 May 2010 00:00:00 GMThttp://hdl.handle.net/10362/40422010-05-01T00:00:00Z